The invention relates to a nut for screw connections. The nut is comprised of two substantially same-size half-shell screw segments that each on their inner side are provided with inner thread segments and are arranged so as to be movable relative to each other until a closed position is reached. Further, means are provided that maintain the nut segments in closed position.
Segmented nuts for use on screws or threaded bolts are known in the prior art. U.S. 2008/0301926 A1 discloses in FIGS. 9C-9F a segmented nut of a total of three identical nut segments. They are embodied like jaws and can be actuated by actuating a rotary ring that is rotatable about a central axis of the nut between an open position and a closed position wherein the jaws carry out a radial movement. In the closed position inner thread segments formed on the inner side of the screw segments engage the outer thread of matching size of a threaded bolt. In the open position, the inner thread sections formed on the segments do not engage the outer thread.
The segmented nut according to U.S. 2008/0301926 A1 is designed and constructed especially for use in a hydraulic tensioning jack. For many other applications in the field of plant and apparatus engineering this segmented nut is however not suitable, particularly because of the drive action by means of a rotary ring that is arranged coaxially to the nut. In practice, this is not suitable for many construction and engineering situations.
DE 1 991 256 discloses a nut for a screw connection with two substantially identically designed nut segments that are pivotable relative to each other and, for this purpose, are pivotably connected with each other at a first end area. For a positive fit (form fit) with the thread of a threaded rod, the nut, with the nut segments in open position, is first pushed onto the thread of the rod as far as possible and the nut segments are closed. Subsequently, the nut is screwed by several turns so that a cylindrically designed longitudinal section of the nut reaches a receptacle in the form of a blind bore; opening of the nut segments from this point on is not possible anymore. The receptacle in the form of a blind bore serves as a closure means that prevents opening of the segments. The disadvantage is that only by a screwing action of several turns a closure of the nut is achieved.
DE 83 08 905 U1 discloses a nut that is suitable for a quick adjustment in axial direction. It is comprised of a housing comprising a ring that can be deflected against a spring force. This ring is provided on one of its inner halves with a thread structure. A pressure spring loads the ring in radial direction so that a positive fit (form fit) of the thread structure with the outer thread of the threaded bolt results. For opening, i.e., releasing the thread engagement, a pivotable lever is provided that is supported in the housing so as to pivot about a pivot axis that is arranged at a right angle to the screw axis. The actuation of the lever leads to a radial, i.e., lateral, displacement of the ring and release of the thread engagement.
The invention has the object to provide a segmented nut that is suitable for many applications in plant and apparatus engineering and is changeable very quickly between the closed position and the open position.